The Dark Green and Cobalt Ringnecks

A most striking new variety of the Ringneck parakeet, and one yet to become widely available, is illustrated on Albert's Ringneck pages. This is the ‘Cobalt’ which, clothed as it is in deep electric blue plumage, more than lives up to its glamorous name. However this is a composite (sometimes called secondary or compound) variety owing its existence to the much less exotic ‘Dark Green’ ; a true primary variety which is also illustrated on Albert's pages. An additional photograph shows both varieties together.

American Origins

The ‘Dark Green’ seems to have made its appearance in the 1980s in America though details, in the usual fashion, are hard to come by and as so often myth and speculation take the place of fact and informed discussion. One story has it that an individual from a number of Grey Greens imported from Germany was paired to a Cinnamon Blue and went on the produce a ‘Dark Green’ hen. (If this account were true might one of those Grey Greens in fact have been an unrecognised ‘Dark Green’ or, perhaps more likely, might Grey Green have been masking or disguising ‘Dark Green’?)

An alternative story tells of a crippled normal Green cock split blue and ino being paired to a very old Turquoise (parblue) hen and this unlikely couple going on to produce the first ‘Dark Green’. The inference here is that a potentially ill-starred pairing of the halt and the decrepit was such as to induce the mutation producing the Dark Green.

The possibilities of this new colour form were soon realised and it wasn’t long before they were cross-paired to Blues. Subsequently, when in turn ‘Dark Greens’ split blue were paired to further Blues it was found that a proportion of the young were a much deeper blue than the normal Blue. Leaping to hasty conclusions, this new deeper blue form was given the name ‘Cobalt’. It would have been better had a genetically neutral name, say Indigo, been chosen until such time as the possibilities of the new variety were fully investigated.

[Note: it now appears that the name ‘Indigo’ has been applied to another recently recognised variety. Since this is said to be a parblue form, the logic of this rather escapes me as by definition indigo is a deep blue verging toward violet with no hint of greeness.]

Good reason?

The names ‘Dark Green’ and ‘Cobalt’, reminding us as they do of the budgerigar varieties using the same names, have a certain significance. Presumably there is good reason why these names were chosen and why two other varieties, the ‘Olive’ and the ‘Mauve’, are listed (though not illustrated) on Albert's pages.

In the budgerigar the Dark Green is produced by a gene (known as the dark gene) which is an incomplete-dominant. Such genes produce two visual types depending upon whether one or two copies of the mutant gene have been inherited (see more comprehensive explanation in The Parblue Puzzle part 2 in these pages). In this case, where one dark gene is present (single-factor) a Dark Green results and where two dark genes are inherited (double-factor) a darker form, called the Olive, is the result. There is also, of course, the normal or wild-type Green where no dark gene is present; giving a total of three shades of green.

Correspondingly, in Blue birds there is the normal Blue which has no dark gene, the Cobalt which has one dark gene (single-factor), and the Mauve which has two dark genes (double-factor).

It has to be assumed that ‘Olive’ and ‘Mauve’ varieties of the Ringneck have been produced. However, I do get the impression that not all breeders are convinced and the possibility of the gene producing the ‘Cobalt’ being more akin to the violet has been aired.

Split blue

It is said that all, or virtually all, present day ‘Dark Green’ ringnecks are split blue and that this was so right from the start. If that first ‘Dark Green’ was indeed split blue, and whether by accident or design was paired to a Blue, the probability is (we now know) that about one in four of any young would be ‘Cobalts’. Any breeder, having once seen this occurrence, would not be easily persuaded to pair his ‘Dark Greens’ any other way. And the ‘Dark Greens’ produced by this pairing, also about one in four, would be split blue and would in their turn be paired to Blues when old enough to breed and so continue a cycle assured of producing a good percentage of these valuable birds.

It does seem that two main pairings are now being used by those breeders fortunate enough to have these birds. That which produces the highest percentage of valuable youngsters is the pairing of a ‘Cobalt’ to a Blue where the young are the same as the parents, 50% ‘Cobalt’ and 50% normal Blue (in the budgerigar this would be referred to as Skyblue).

The second pairing is that already referred to above, a ‘Dark Green’ (invariably split blue) to a Blue. This is reported to produce normal Greens split blue, Blues, ‘Dark Greens’ split blue, and ‘Cobalts’, in equal proportions; that is 25% of each. These results are of concern to those well versed in budgerigar genetics. Because of a process known as linkage the corresponding pairing in the budgerigar, although producing the same varieties of young, would do so in distinctly different proportions.

So we come back to the identity of the gene producing the ‘Dark Green’ and the ‘Cobalt’ in the ringneck. Is it a dark gene acting as an incomplete-dominant producing three distinct visual types (phenotypes)? Is it something similar to the violet gene which, in the budgerigar, is also an incomplete dominant producing three visual types (see article The Facts About Violet Budgerigars by Peter Bergman in these pages)? Or is it a similar, but fully dominant gene, which will only ever produce one mutant form? In short, are the ‘Olive’ and ‘Mauve’ ringnecks birds of substance and reality or mere flights of premature fancy?

European dimension

It is also reported that a number of years after the discovery of the ‘Dark Green’ in America a ringneck of similar appearance occurred in Europe; almost certainly Holland or Belgium. This also produced birds of a ‘Cobalt’ appearance when paired to a Blue. Perhaps surprisingly, there are said to be small but significant differences in appearance between the two types of ‘Cobalt’ and it remains to be seen how they compare from the genetic viewpoint.

Copyright: Clive Hesford, August 1998 (with revisions to November 2001)